Males and females may exhibit different responses to testing of adrenal function. The hormones responsible for controlling adrenal function are ACTH (adrenocorticotropic hormone or corticotropin) and CRH (corticotropin-releasing hormone). Adrenal function is tested with an ACTH stimulation test. ACTH stimulates the adrenal glands to produce cortisol. Cortisol levels are measured, and a certain peak level indicates normal adrenal gland function. Females may produce more cortisol in response to ACTH testing than males. This difference may be due to certain proteins, called G proteins. The hormones controlling adrenal function, ACTH and CRH, work through G proteins. Females may have more G proteins than males allowing for the increased cortisol response to ACTH stimulation.